U.S. patent application number 13/464164 was filed with the patent office on 2013-11-07 for cold start engine control systems and methods.
This patent application is currently assigned to GM Global Technology Operations LLC. The applicant listed for this patent is Joshua D. Cowgill, Bruce F. Hunter, Craig D. Marriott, Claudio Engler Pinto, Ricardo Vincenzi. Invention is credited to Joshua D. Cowgill, Bruce F. Hunter, Craig D. Marriott, Claudio Engler Pinto, Ricardo Vincenzi.
Application Number | 20130297182 13/464164 |
Document ID | / |
Family ID | 49513231 |
Filed Date | 2013-11-07 |
United States Patent
Application |
20130297182 |
Kind Code |
A1 |
Vincenzi; Ricardo ; et
al. |
November 7, 2013 |
COLD START ENGINE CONTROL SYSTEMS AND METHODS
Abstract
A control system includes a starter control module, a mode
setting module, a throttle control module, and a fuel control
module. The starter control module initiates cranking of a spark
ignition direct injection (SIDI) engine in response to user
actuation of an ignition switch. The mode setting module sets a
mode of operation to a coldstart mode when an engine coolant
temperature is less than a predetermined temperature during the
cranking. The throttle control module allows a throttle valve to be
biased to a predetermined open position when the SIDI engine is off
and, in response to the setting of the mode to the coldstart mode,
selectively closes the throttle valve relative to the predetermined
open position during the cranking. The fuel control module, in
response to the setting of the mode to the coldstart mode, disables
direct injection of fuel for a first combustion event during the
cranking.
Inventors: |
Vincenzi; Ricardo; (Sao
Caetano do Sul, BR) ; Hunter; Bruce F.; (Okemos,
MI) ; Cowgill; Joshua D.; (Hartland, MI) ;
Marriott; Craig D.; (Clawson, MI) ; Pinto; Claudio
Engler; (Indaiatuba, BR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Vincenzi; Ricardo
Hunter; Bruce F.
Cowgill; Joshua D.
Marriott; Craig D.
Pinto; Claudio Engler |
Sao Caetano do Sul
Okemos
Hartland
Clawson
Indaiatuba |
MI
MI
MI |
BR
US
US
US
BR |
|
|
Assignee: |
GM Global Technology Operations
LLC
Detroit
MI
|
Family ID: |
49513231 |
Appl. No.: |
13/464164 |
Filed: |
May 4, 2012 |
Current U.S.
Class: |
701/103 |
Current CPC
Class: |
F02D 2200/021 20130101;
Y02T 10/40 20130101; Y02T 10/44 20130101; F02D 41/062 20130101;
F02D 2200/0611 20130101; F02D 41/401 20130101; F02N 15/00 20130101;
F02N 19/02 20130101; F02D 41/064 20130101; F02D 2200/0406 20130101;
Y02T 10/42 20130101; F02N 11/08 20130101; F02N 19/00 20130101; Y02T
10/30 20130101; F02D 41/0002 20130101; F02D 19/087 20130101; F02D
41/0025 20130101; F02D 19/084 20130101; F02D 37/02 20130101; F02P
5/1506 20130101; Y02T 10/36 20130101 |
Class at
Publication: |
701/103 |
International
Class: |
F02D 41/30 20060101
F02D041/30; F02D 41/26 20060101 F02D041/26; F02D 28/00 20060101
F02D028/00 |
Claims
1. A cold start control system for a vehicle, comprising: a starter
control module that initiates cranking of a spark ignition direct
injection (SIDI) engine in response to user actuation of an
ignition switch; a mode setting module that sets a mode of
operation to a coldstart mode when an engine coolant temperature is
less than a predetermined temperature during the cranking; a
throttle control module that allows a throttle valve to be biased
to a predetermined open position when the SIDI engine is off and
that, in response to the setting of the mode to the coldstart mode,
selectively closes the throttle valve relative to the predetermined
open position during the cranking; and a fuel control module that,
in response to the setting of the mode to the coldstart mode,
disables direct injection of fuel for a first combustion event
during the cranking.
2. The cold start control system of claim 1 wherein the fuel
control module, in response to the setting of the mode to the
coldstart mode, selectively injects fuel into a cylinder while an
intake valve of the cylinder is open for a second combustion event
during the cranking.
3. The cold start control system of claim 1 wherein the
predetermined temperature is less than a flash point temperature of
the fuel.
4. The cold start control system of claim 1 further comprising a
parameter determination module that determines a percentage of
ethanol in the fuel, wherein the mode setting module sets the
predetermined temperature based on the percentage of ethanol in the
fuel.
5. The cold start control system of claim 1 wherein the
predetermined temperature is one of less than and equal to 18
degrees Celsius.
6. The cold start control system of claim 1 wherein the fuel
includes ethanol.
7. The cold start control system of claim 1 wherein, in response to
the setting of the mode to the coldstart mode, the throttle control
module closes the throttle valve to a predetermined fully closed
position during the cranking.
8. The cold start control system of claim 1 wherein, in response to
the setting of the mode to the coldstart mode, the throttle control
module closes the throttle valve based on a target intake manifold
pressure during the cranking.
9. The cold start control system of claim 8 wherein the target
intake manifold pressure is a predetermined pressure that is less
than ambient air pressure.
10. The cold start control system of claim 1 further comprising a
spark control module that, in response to the setting of the mode
to the coldstart mode, disables spark for a second combustion event
during the cranking.
11. A cold start control method for a vehicle, comprising:
initiating cranking of a spark ignition direct injection (SIDI)
engine in response to user actuation of an ignition switch; setting
a mode of operation to a coldstart mode when an engine coolant
temperature is less than a predetermined temperature during the
cranking; allowing a throttle valve to be biased to a predetermined
open position when the SIDI engine is off; in response to the
setting of the mode to the coldstart mode, selectively closing the
throttle valve relative to the predetermined open position during
the cranking; and, in response to the setting of the mode to the
coldstart mode, disabling direct injection of fuel for a first
combustion event during the cranking.
12. The cold start control method of claim 11 further comprising,
in response to the setting of the mode to the coldstart mode,
selectively injecting fuel into a cylinder while an intake valve of
the cylinder is open for a second combustion event during the
cranking.
13. The cold start control method of claim 11 wherein the
predetermined temperature is less than a flash point temperature of
the fuel.
14. The cold start control method of claim 11 further comprising:
determining a percentage of ethanol in the fuel; and setting the
predetermined temperature based on the percentage of ethanol in the
fuel.
15. The cold start control method of claim 11 wherein the
predetermined temperature is one of less than and equal to 18
degrees Celsius.
16. The cold start control method of claim 11 wherein the fuel
includes Ethanol.
17. The cold start control method of claim 11 further comprising,
in response to the setting of the mode to the coldstart mode,
closing the throttle valve to a predetermined fully closed position
during the cranking.
18. The cold start control method of claim 11 further comprising,
in response to the setting of the mode to the coldstart mode,
closing the throttle valve based on a target intake manifold
pressure during the cranking.
19. The cold start control method of claim 18 wherein the target
intake manifold pressure is a predetermined pressure that is less
than ambient air pressure.
20. The cold start control method of claim 11 further comprising,
in response to the setting of the mode to the coldstart mode,
disabling spark for a second combustion event during the cranking.
Description
FIELD
[0001] The present disclosure relates to internal combustion
engines and more particularly to engine control systems and methods
for cold engine startups.
BACKGROUND
[0002] The background description provided herein is for the
purpose of generally presenting the context of the disclosure. Work
of the presently named inventors, to the extent it is described in
this background section, as well as aspects of the description that
may not otherwise qualify as prior art at the time of filing, are
neither expressly nor impliedly admitted as prior art against the
present disclosure.
[0003] Internal combustion engines combust air and fuel within
cylinders to produce drive torque. Air flow into an engine may be
regulated via a throttle valve. A fuel control system controls fuel
injection amount and timing. Increasing the amount of air and fuel
provided to the cylinders generally increases the torque output of
the engine.
[0004] Spark ignition direct injection (SIDI) engines have improved
fuel economy and increased power over port fuel-injected combustion
engines. A fuel injection system for an SIDI engine is operated at
high pressure to inject fuel directly into combustion chambers. A
fuel pump for supplying the fuel to a fuel rail at high pressure is
mechanically driven by the engine.
SUMMARY
[0005] A cold start control system for a vehicle includes a starter
control module, a mode setting module, a throttle control module,
and a fuel control module. The starter control module initiates
cranking of a spark ignition direct injection (SIDI) engine in
response to user actuation of an ignition switch. The mode setting
module sets a mode of operation to a coldstart mode when an engine
coolant temperature is less than a predetermined temperature during
the cranking. The throttle control module allows a throttle valve
to be biased to a predetermined open position when the SIDI engine
is off and, in response to the setting of the mode to the coldstart
mode, selectively closes the throttle valve relative to the
predetermined open position during the cranking. The fuel control
module, in response to the setting of the mode to the coldstart
mode, disables direct injection of fuel for a first combustion
event during the cranking.
[0006] A cold start control method for a vehicle, includes:
initiating cranking of a spark ignition direct injection (SIDI)
engine in response to user actuation of an ignition switch; setting
a mode of operation to a coldstart mode when an engine coolant
temperature is less than a predetermined temperature during the
cranking; and allowing a throttle valve to be biased to a
predetermined open position when the SIDI engine is off. The cold
start control method further includes: in response to the setting
of the mode to the coldstart mode, selectively closing the throttle
valve relative to the predetermined open position during the
cranking; and, in response to the setting of the mode to the
coldstart mode, disabling direct injection of fuel for a first
combustion event during the cranking.
[0007] Further areas of applicability of the present disclosure
will become apparent from the detailed description provided
hereinafter. It should be understood that the detailed description
and specific examples are intended for purposes of illustration
only and are not intended to limit the scope of the disclosure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] The present disclosure will become more fully understood
from the detailed description and the accompanying drawings,
wherein:
[0009] FIG. 1 is a functional block diagram of an example spark
ignition direct injection (SIDI) engine system according to the
present disclosure;
[0010] FIG. 2 is a functional block diagram of an example startup
control module according to the present disclosure; and
[0011] FIG. 3 is a flowchart depicting an example method of
performing a cold start of an SIDI engine according to the present
disclosure.
DETAILED DESCRIPTION
[0012] A spark ignition direct injection (SIDI) engine combusts air
and fuel to generate drive torque for a vehicle. The fuel is
injected directly into cylinders of SIDI engines. The fuel may be
gasoline, a mixture of gasoline and ethanol, or another suitable
type of fuel. Engines that can combust gasoline, ethanol, and a
mixture of gasoline and ethanol can be referred to as flex fuel
engines.
[0013] A control module selectively starts an SIDI engine in
response to user actuation of an ignition input, such as an
ignition key or button, or initiation of an auto-start event. The
control module controls various operating parameters during startup
of the SIDI engine and while the SIDI engine is ON (running) after
startup. For example, the control module controls opening of a
throttle valve, fuel injection amount and timing, spark timing, and
other suitable operating parameters during startup of the SIDI
engine and while the SIDI engine is ON after startup. The control
module also selectively shuts down the SIDI engine in response to
user actuation of an ignition input or initiation of an auto-stop
event.
[0014] Different types of fuel have different flash point
temperatures. The flash point temperature of a fuel may refer to a
minimum temperature at which the fuel can vaporize to form an
ignitable mixture in air. At temperatures that are less than the
flash point temperature of the fuel that is directly injected into
the SIDI engine, the fuel may be unable to vaporize during startup,
and the SIDI engine may be unable to start.
[0015] One or more auxiliary devices can be added to facilitate
startup of the SIDI engine at temperatures that are less than the
flash point temperature of the fuel. For example, a block heater
and/or a fuel rail heater or a fuel injector heater may be added to
warm the fuel. Warming the fuel may enable the fuel to vaporize
sufficiently to allow startup of the SIDI engine at temperatures
that are less than the flash point temperature of the fuel. For
another example, as gasoline has a low flash point temperature
relative to other types of fuels, a separate gasoline tank and a
gasoline injector can be added for use during startup of engines
using a fuel having a high flash point temperature, such as
Ethanol. Adding one or more auxiliary devices, however, increases
vehicle cost.
[0016] According to the present disclosure, no auxiliary devices
are added. Instead, at temperatures that are at or less than the
flash point temperature of the fuel that is directly injected into
the cylinders of the SIDI engine, the control module selectively
controls the throttle valve, fueling, and spark during startup of
the SIDI engine as to enable startup of the SIDI engine.
[0017] Referring now to FIG. 1, a functional block diagram of an
example engine system 100 is presented. The engine system includes
an engine 102 that combusts an air/fuel mixture to produce drive
torque for a vehicle. Air is drawn into an intake manifold 104
through a throttle valve 106. The throttle valve 106 regulates air
flow into the intake manifold 104. Air within the intake manifold
104 is drawn into cylinders of the engine 102, such as cylinder
108.
[0018] One or more fuel injectors, such as fuel injector 110,
inject fuel that mixes with air to form an air/fuel mixture. In
various implementations, one fuel injector may be provided for each
cylinder of the engine 102. The fuel injectors inject fuel directly
into the cylinders. Fuel injection may be controlled based on a
desired air/fuel mixture for combustion, such as a stoichiometric
air/fuel mixture. A fuel system provides fuel to the fuel
injectors. The fuel system is discussed further below.
[0019] An intake valve 112 opens to allow air into the cylinder
108. A piston (not shown) compresses the air/fuel mixture within
the cylinder 108. A spark plug 114 initiates combustion of the
air/fuel mixture within the cylinder 108. One spark plug may be
provided for each cylinder of the engine 102. Combustion of the
air/fuel mixture applies force to the piston, and the piston drives
rotation of a crankshaft (not shown).
[0020] The engine 102 outputs torque via the crankshaft. A flywheel
120 is coupled to the crankshaft and rotates with the crankshaft.
Torque output by the engine 102 is selectively transferred to a
transmission 122 via a torque transfer device 124. The torque
transfer device 124 selectively couples/decouples the transmission
122 to/from the engine 102. The transmission 122 may include, for
example, a manual transmission, an automatic transmission, a
semi-automatic transmission, an auto-manual transmission, or
another suitable type of transmission. The torque transfer device
124 may include, for example, a torque converter and/or one or more
clutches.
[0021] Exhaust produced by combustion of the air/fuel mixture is
expelled from the cylinder 108 via an exhaust valve 126. The
exhaust is expelled from the cylinders to an exhaust system 128.
The exhaust system 128 may treat the exhaust before the exhaust is
expelled from the exhaust system 128. Although one intake and
exhaust valve are shown and described as being associated with the
cylinder 108, more than one intake and/or exhaust valve may be
associated with each cylinder of the engine 102.
[0022] An engine control module (ECM) 130 controls various engine
actuators. The engine actuators may include, for example, a
throttle actuator module 132, a fuel actuator module 134, and a
spark actuator module 136. The engine system 100 may also include
other engine actuators, and the ECM 130 may control the other
engine actuators.
[0023] Each engine actuator controls an operating parameter based
on a signal from the ECM 130. For example only, based on signals
from the ECM 130, the throttle actuator module 132 may control
opening of the throttle valve 106, the fuel actuator module 134 may
control fuel injection amount and timing, and the spark actuator
module 136 may control spark timing.
[0024] The ECM 130 may control the engine actuators based on, for
example, driver inputs and inputs from various vehicle systems. The
vehicle systems may include, for example, a transmission system, a
hybrid control system, a stability control system, a chassis
control system, and other suitable vehicle systems.
[0025] A driver input module 140 may provide the driver inputs to
the ECM 130. The driver inputs provided to the ECM 130 may include,
for example, an accelerator pedal position (APP), a brake pedal
position (BPP), cruise control inputs, and vehicle operation
commands. An APP sensor 142 measures position of an accelerator
pedal (not shown) and generates the APP based on the position of
the accelerator pedal. A BPP sensor 144 monitors actuation of a
brake pedal (not shown) and generates the BPP based on a position
of the brake pedal. A cruise control system 146 provides the cruise
control inputs, such as a desired vehicle speed, based on inputs to
the cruise control system 146.
[0026] The vehicle operation commands may include, for example,
vehicle startup commands and vehicle shutdown commands. The vehicle
operation commands may be input by a user via actuation of one or
more ignition system inputs 148. For example, a user may input the
vehicle operation commands by actuating an ignition key, one or
more buttons/switches, and/or one or more other suitable ignition
system inputs.
[0027] An engine speed sensor 152 measures rotational speed of the
engine 102 and generates an engine speed based on the speed. For
example only, the engine speed sensor 152 may generate the engine
speed based on rotation of the crankshaft in revolutions per minute
(rpm). A coolant temperature sensor 154 measures a temperature of
engine coolant and generates an engine coolant temperature (ECT)
based on the temperature of the engine coolant. The ECM 130 may
also receive operating parameters measured by other sensors 156,
such as oxygen in the exhaust, intake air temperature (IAT), mass
air flowrate (MAF), oil temperature, manifold absolute pressure
(MAP), and/or other suitable parameters. In various
implementations, ethanol content may be measured using a
sensor.
[0028] The ECM 130 selectively shuts down the engine 102 when a
user inputs a vehicle shutdown command. For example only, the ECM
130 may disable the injection of fuel, disable the provision of
spark, and perform other shutdown operations to shut down the
engine 102 in response to receipt of a vehicle shutdown
command.
[0029] The ECM 130 selectively starts the engine 102. The ECM 130
starts the engine 102 in response to receipt of a vehicle startup
command or initiation of an auto-start event. The ECM 130 engages a
starter motor 160 with the engine 102 to initiate engine startup.
The starter motor 160 may engage the flywheel 120 or other suitable
component(s) that drive rotation of the crankshaft.
[0030] A starter motor actuator 162, such as a solenoid,
selectively engages the starter motor 160 with the engine 102. A
starter actuator module 164 controls the starter motor actuator 162
and the starter motor 160 based on signals from the ECM 130. For
example only, the ECM 130 may command engagement of the starter
motor 160 when the vehicle startup command is received. The starter
actuator module 164 selectively applies current to the starter
motor 160 when the starter motor 160 is engaged with the engine
102. The application of current to the starter motor 160 drives the
starter motor 160, and the starter motor 160 drives the
crankshaft.
[0031] Once the crankshaft is rotating, the starter motor 160 may
be disengaged from the engine 102, and the flow of current to the
starter motor 160 may be discontinued. The engine 102 may be deemed
running, for example, when the engine speed exceeds a predetermined
speed, such as approximately 700 rpm or another suitable speed. The
period between when the starter motor 160 is engaged with the
engine 102 for starting the engine and when the engine 102 is
deemed running may be referred to as engine cranking.
[0032] The current provided to the starter motor 160 may be
provided by, for example, a battery 170. While only the battery 170
is shown, the battery 170 may include one or more individual
batteries that are connected together or one or more other
batteries may be provided.
[0033] The engine system 100 may include one or more electric
motors, such as electric motor (EM) 172. The EM 172 may selectively
draw electrical power, for example, to supplement the torque output
of the engine 102. The EM 172 may also selectively function as a
generator and selectively apply a braking torque to the engine 102
to generate electrical power. Generated electrical power may be
used, for example, to charge the battery 170, to provide electrical
power to one or more other EMs (not shown), to provide electrical
power to other vehicle systems, and/or for other suitable uses.
[0034] As mentioned above, the fuel system supplies fuel to the
fuel injectors. The fuel system may include a fuel tank 174, a low
pressure fuel pump 176, a high pressure fuel pump 178, a fuel rail
180, a pressure relief valve 182, and/or one or more other suitable
components. The low pressure fuel pump 176 draws fuel from the fuel
tank 174 and provides fuel at low pressures to the high pressure
fuel pump 178. The low pressures provided by the low pressure fuel
pump 176 are expressed relative to pressurization provided by the
high pressure fuel pump 178.
[0035] The low pressure fuel pump 176 is an electrically driven
fuel pump, and a pump actuator module 184 may control the
application of power to the low pressure fuel pump 176 based on
signals from the ECM 130. For example only, the ECM 130 may command
application of power to the low pressure fuel pump 176 when or
before a vehicle startup command is input.
[0036] The high pressure fuel pump 178 pressurizes the fuel
received from the low pressure fuel pump 176 within the fuel rail
180. The high pressure fuel pump 178 is engine driven, such as by
the crankshaft or by a camshaft. The high pressure fuel pump 178
may pump fuel into the fuel rail 180, for example, once, twice, or
more per revolution of the crankshaft.
[0037] The fuel injectors inject fuel from the fuel rail 180 into
the cylinders. The high pressure fuel pump 178 pressurizes the fuel
within the fuel rail 180 to pressures that are greater than
pressure within the cylinder during fuel injection. When a pressure
within the fuel rail 180 is greater than a predetermined maximum
pressure, the pressure relief valve 182 releases fuel back to the
fuel tank 174.
[0038] As fuel is injected directly into the cylinders and
combustion is initiated via spark, the engine 102 may be referred
to as a spark ignition direct injection (SIDI) engine. Flex fuel
SIDI engines can combust gasoline, a blend of gasoline and ethanol,
or ethanol. An ethanol fuel may be referred to using the prefix E
and an integer corresponding to an amount of ethanol in the blend
by volume. For example, E85 may refer to a blend of gasoline and
ethanol that includes 85 percent ethanol by volume, E50 may refer
to a blend of gasoline and ethanol that includes up to 50 percent
ethanol by volume, etc. Ethanol may be referred to as E100, and
gasoline may be referred to as E0. Other types of fuels that may be
combusted by SIDI engines include methanol, other alcohol based
fuels, liquefied petroleum gas (LPG), propane, butane, etc.
[0039] Flash point temperature of a fuel may refer to a minimum
temperature at which the fuel can vaporize to form an ignitable
mixture in air. Some fuels, such as gasoline, have a flash point
temperature that is less than a predetermined minimum temperature,
such as -10 degrees Celsius (.degree. C.). Other fuels, however,
have a flash point temperature that is greater than the
predetermined minimum temperature. For example only, E100 may have
a flash point temperature of approximately 18.degree. C. Fuels
having a flash point temperature that is greater than the
predetermined minimum temperature may be unable to vaporize and/or
combust when the engine 102 is started at or even above the
predetermined minimum temperature.
[0040] One or more auxiliary devices could be added to the vehicle
to enable startup of the engine 102 at temperatures that are less
than the flash point temperature of the fuel within the fuel tank
174. For example only, a gasoline injector and a separate gasoline
fuel tank can be added, and the gasoline can be injected during
engine cranking to enable startup of the engine 102. For another
example only, an engine block heater and/or one or more other
electrical heaters, such as a fuel rail heater or fuel injector
heaters, can be added to warm the fuel to enable startup of the
engine 102. The addition of one or more of these auxiliary, startup
enabling devices, however, also increases vehicle cost.
[0041] In the present patent application, zero auxiliary devices
(e.g, engine block heater, separate gasoline injector, separate
gasoline fuel tank, and/or one or more electrical heaters) are
included to facilitate engine startup at temperatures that are less
than the flash point temperature of the fuel within the fuel tank
174. Instead, at temperatures that are less than the flash point
temperature of the fuel within the fuel tank 174, a startup control
module 190 selectively closes the throttle valve 106 and controls
fueling during engine cranking to enable vaporization of the fuel
and to start the engine 102.
[0042] Referring now to FIG. 2, a functional block diagram of an
example implementation of the startup control module 190 is
presented. In response to a user inputting a vehicle startup
command 204 while the engine 102 is off, a starter control module
208 commands the starter actuator module 164 to engage the starter
motor 160 with the engine 102 and apply power to the starter motor
160. The vehicle startup command 204 may be input by the driver,
for example, by actuating one or more ignition inputs.
[0043] The starter actuator module 164 engages the starter motor
160 with the engine 102 and applies power to the starter motor 160
in response to the command. When engaged with the engine 102 and
receiving power, the starter motor 160 drives rotation of the
crankshaft. Power is also applied to the low pressure fuel pump 176
during engine cranking. Power may be applied to the low pressure
fuel pump 176 beginning before power is applied to the starter
motor 160. The low pressure fuel pump 176 may be controlled during
engine cranking and while the engine 102 is running based on
providing fuel to the high pressure fuel pump 178 at a
predetermined low pressure. The high pressure fuel pump 178
increases the pressure of the fuel within the fuel rail 180 as the
starter motor 160 drives the crankshaft.
[0044] A throttle control module 212 controls opening of the
throttle valve 106. The throttle control module 212 may set a
desired area 216 for the throttle valve 106, and the throttle
actuator module 132 may actuate the throttle valve 106 based on the
desired area 216. A fuel control module 220 controls amount and
timing of fuel injection. The fuel control module 220 may set
desired fueling parameters 224 (e.g., desired amount, desired
timing, desired number of pulses, etc.), and the fuel actuator
module 134 may control the fuel injectors based on the desired
fueling parameters 224.
[0045] While the engine 102 is off pursuant to receipt of a vehicle
shutdown command, the throttle control module 212 may de-energize
the throttle valve 106. When de-energized, the throttle valve 106
may be biased (mechanically) to a predetermined open position. The
throttle valve 106 may be biased against one or more stops. When in
the predetermined open position, a predetermined open area is
achieved, such as approximately 80 percent open.
[0046] The opening of the throttle valve 106 should be at
approximately the predetermined open position at the time when the
vehicle startup command 204 is received. Additionally, pressure
within the intake manifold 104 should be approximately equal to
ambient air pressure when the vehicle startup command 204 is
received. As stated above, the fuel within the fuel tank 174 may be
unable to vaporize and the engine 102 may be unable to start at
temperatures that are less than the flash point temperature of the
fuel.
[0047] A mode setting module 228 sets a mode 232 of operation for
the engine 102. The throttle control module 212 and the fuel
control module 220 control the throttle valve 112 and fuel
injection, respectively, based on the mode 232. Control modules of
one or more other engine actuators may also control the other
engine actuators based on the mode 232.
[0048] The mode setting module 228 may set the mode 232 to a
coldstart mode in response to the receipt of the vehicle startup
command 204 and a determination that a temperature is less than a
predetermined temperature. For example, the mode setting module 228
may set the mode 232 to the coldstart mode when an ECT (engine
coolant temperature) 236 is less than the predetermined
temperature. The predetermined temperature is less than the flash
point temperature of the fuel within the fuel tank 174. The
predetermined temperature may be a predetermined value that is less
than or equal to 18 degrees Celsius (.degree. C.) or another
suitable temperature below which the fuel within the fuel tank 174
may be unable to vaporize during engine cranking. When the
temperature is not less than the predetermined temperature, the
mode setting module 228 may set the mode 232 to a start mode for a
normal engine startup.
[0049] In various implementations, a parameter determination module
240 may be included. The parameter determination module 240 may
determine a characteristic 244 of the fuel within the fuel tank
174. For example only, the parameter determination module 240 may
determine a percentage of ethanol in the fuel within the fuel tank
174. The parameter determination module 240 may determine the
characteristic 244 of the fuel within the fuel tank 174, for
example, based on measurements provided by a fuel sensor, cylinder
pressures, or other suitable parameters.
[0050] The mode setting module 228 may set the predetermined
temperature (used for determining whether to set the mode 232 to
the coldstart mode) based on the characteristic 244. For example
only, the mode setting module 228 may set the predetermined
temperature using a function or a mapping (e.g., lookup table) that
relates the characteristic 244 of the fuel within the fuel tank 174
to the predetermined temperature.
[0051] In response to the mode 232 being set to the coldstart mode,
the throttle control module 212 and the fuel control module 220
control the throttle valve 112 and fuel injection for a cold start
of the engine 102. More specifically, when the mode 232 is set to
the coldstart mode, the throttle control module 212 selectively
closes the throttle valve 112 relative to the predetermined open
position during engine cranking. Closing the throttle valve 112
increases the vacuum (i.e., lowers the pressure) within the intake
manifold 104 and the cylinders. The lower pressure within the
intake manifold 104 may provide better conditions for vaporization
when the fuel is injected into a cylinder.
[0052] The throttle control module 212 may close the throttle valve
112 to a predetermined fully closed position during engine cranking
when the mode 232 is set to the cold start mode. When the throttle
valve 112 is in the predetermined fully closed position, a
predetermined fully closed area is achieved, such as approximately
zero percent open.
[0053] In various implementations, the throttle control module 212
may close the throttle valve 112 based on adjusting the pressure
within the intake manifold 104 to a target pressure when the mode
232 is set to the cold start mode. The target pressure may be a
predetermined pressure that is less than ambient air pressure. The
throttle control module 212 may control the throttle valve 112 in
closed-loop based on measurements provided by a MAP sensor and the
target pressure.
[0054] When the mode 232 is set to the cold start mode, the fuel
control module 220 generally provides rich fueling for combustion
events. However, the fuel control module 220 may disable fuel
injection for one or more combustion events when the mode 232 is
set to the coldstart mode. The fuel control module 220 may disable
fuel injection, for example, for one or more of the combustion
events that would occur soonest after the starter motor 160 begins
cranking the engine 102. Disabling fuel injection for a combustion
event allows the high pressure fuel pump 178 to increase the
pressure within the fuel rail 180. The pressure within the fuel
rail 180 being higher may increase vaporization of fuel injected
into a cylinder and increase temperature of the walls and body of
the cylinder.
[0055] Injection of fuel for a given combustion event may be
accomplished using one or more individual injections of fuel. When
the mode 232 is set to the coldstart mode, the fuel control module
220 may command one injection of fuel for a combustion event of a
cylinder be performed while the intake valve(s) of the cylinder is
open for the combustion event. The lower pressure within the intake
manifold 104 that is attributable to the closing of the throttle
valve 112 may enable the fuel that is injected while the intake
valve(s) is open to vaporize to a greater extent. The fuel control
module 220 may also command one or more other fuel injections for
the combustion event be performed after the intake valve of the
cylinder is closed for the combustion event. The fuel and air
charge temperature increase during the cylinder compression event
can therefore occur at a lower pressure due to the lower intake
manifold pressure and thus enable the fuel to vaporize to a greater
extent.
[0056] A spark control module 248 sets a desired spark timing 252,
and the spark actuator module 136 generates spark based on the
desired spark timing 252. When the mode 232 is set to the coldstart
mode, the spark control module 248 may disable spark for one or
more combustion events. Disabling spark for a combustion event may
enable a charge of air and fuel to warm within a cylinder. This may
enable more fuel of the charge to vaporize when it is combusted
during a later combustion event.
[0057] The mode setting module 228 may transition the mode 232 from
the coldstart mode (or the start mode) to an engine running mode
when the engine is running after a startup. The mode setting module
228 may transition the mode 232 to the engine running mode, for
example, when an engine speed becomes greater than a predetermined
speed, such as approximately 700 rpm or another suitable speed. The
throttle control module 212, the fuel control module 220, and the
spark control module 248 may transition to normal control of the
throttle valve 112, fueling, and spark timing in response to a
transition in the mode 232 to the engine running mode.
[0058] Referring now to FIG. 3, a flowchart depicting an example
method of performing a cold start of the engine 102 is presented.
Control may begin with 304 at a time when the engine 102 is off
pursuant to a vehicle shutdown request. At 304, control determines
whether a user has input a vehicle startup command. If true,
control continues with 308. If false, control remains at 304 and
waits for a user to input a vehicle startup command. A user may
input a vehicle startup command by actuating an ignition switch, an
ignition button, etc.
[0059] At 308, control engages the starter motor 160 with the
engine 102 and applies power to the starter motor 160. The starter
motor 160 drives rotation of the crankshaft of the engine 102. The
low pressure fuel pump 176 may be activated to begin pumping fuel
to the high pressure fuel pump 178 before the starter motor 160
begins driving the crankshaft. The high pressure fuel pump 178
pumps fuel into the fuel rail 180 as the starter motor 160 drives
the crankshaft.
[0060] Control may obtain a characteristic of the fuel within the
fuel tank 174 at 312. The characteristic of the fuel may be, for
example, an ethanol concentration of the fuel, a flash point
temperature of the fuel, or another suitable characteristic of the
fuel. At 316, control may set the predetermined temperature used in
determining whether the startup of the engine 102 is a cold start
based on the characteristic of the fuel.
[0061] At 320, control may determine whether the ECT 236 is less
than the predetermined temperature. If true, control may continue
with 324 and perform a coldstart of the engine 102. If false,
control may perform a normal startup of the engine 102 at 322, and
control may end. The predetermined temperature is less than the
flash point temperature of the fuel and may be less than or equal
to +18.degree. C.
[0062] At 324, control regulates the throttle valve 112, fuel
injection, and spark timing for the coldstart of the engine 102.
More specifically, control closes the throttle valve 112 from the
predetermined open position during engine cranking. Control may
close the throttle valve 112 to the predetermined fully closed
position or regulate the throttle valve 112 based on achieving the
target MAP. Control may command an injection of fuel for a
combustion event of a cylinder while the intake valve is open for
the cylinder. Control may additionally or alternatively disable
fuel injections for one or more combustion events during engine
cranking. Control may disable spark for one or more combustion
events during engine cranking. A combination of one or more of the
above may enable fuel injected into the cylinders to vaporize and
allow the engine 102 to start. Control may also alter the injected
quantity of fuel on a cylinder event basis.
[0063] At 328, control may determine whether the engine 102 is
running. If true, control may transition to controlling the
throttle valve 112, fuel injection, and spark timing in a normal
operation mode at 332, and control may end. If false, control may
return to 324 and continue controlling the throttle valve 112, fuel
injection, and spark timing for the coldstart of the engine 102.
The engine 102 may be deemed running, for example, when the engine
speed is greater than the predetermined speed.
[0064] The foregoing description is merely illustrative in nature
and is in no way intended to limit the disclosure, its application,
or uses. The broad teachings of the disclosure can be implemented
in a variety of forms. Therefore, while this disclosure includes
particular examples, the true scope of the disclosure should not be
so limited since other modifications will become apparent upon a
study of the drawings, the specification, and the following claims.
For purposes of clarity, the same reference numbers will be used in
the drawings to identify similar elements. As used herein, the
phrase at least one of A, B, and C should be construed to mean a
logical (A or B or C), using a non-exclusive logical OR. It should
be understood that one or more steps within a method may be
executed in different order (or concurrently) without altering the
principles of the present disclosure.
[0065] As used herein, the term module may refer to, be part of, or
include an Application Specific Integrated Circuit (ASIC); an
electronic circuit; a combinational logic circuit; a field
programmable gate array (FPGA); a processor (shared, dedicated, or
group) that executes code; other suitable hardware components that
provide the described functionality; or a combination of some or
all of the above, such as in a system-on-chip. The term module may
include memory (shared, dedicated, or group) that stores code
executed by the processor.
[0066] The term code, as used above, may include software,
firmware, and/or microcode, and may refer to programs, routines,
functions, classes, and/or objects. The term shared, as used above,
means that some or all code from multiple modules may be executed
using a single (shared) processor. In addition, some or all code
from multiple modules may be stored by a single (shared) memory.
The term group, as used above, means that some or all code from a
single module may be executed using a group of processors. In
addition, some or all code from a single module may be stored using
a group of memories.
[0067] The apparatuses and methods described herein may be
implemented by one or more computer programs executed by one or
more processors. The computer programs include processor-executable
instructions that are stored on a non-transitory tangible computer
readable medium. The computer programs may also include stored
data. Non-limiting examples of the non-transitory tangible computer
readable medium are nonvolatile memory, magnetic storage, and
optical storage.
* * * * *